Windows suddenly fogged up!

It was 7 deg this morning. I was going about 50 mph with air on half defrost and floor. Did not have recirc on. Engine was up to temp and blowing hot air. All of a sudden the all windows fogged up including the windshield. Even the plastic over the gauges fogged. Heater core is not leaking. Fresh powder snow was blowing off of the hood so I’m wondering if some of the powder got sucked in to the blower. Any ideas?.

 

Curious if the fogging was on the inside or outside? And, were you driving past a feed lot about that time?

 

This has happened to me with multiple vehicles in the past, I would say it's normal. Has something to do with the snow on the hood rapidly cooling stuff down. I wouldn't worry about it, brush the snow off or be aware and in a position to expect it might happen. Hell, it happened to me this morning. No biggy.

 

I live up in Canada and I would say turn your AC on when you have the heat cranked on defrost And the evaporator should suck the moisture out quicker.. I have had some vehicles up here where the AC didn’t work And the windows would fog up really bad. I am no car expert I just have had to deal with this numerous times. My Honda accord was terrible.

 

it was on the inside. The scary thing was how quick it happened. Couldn’t see the road. I think when the selector is half defrost and floor the compressor cycles. It didn’t take me long to go full defrost and hit the ac button! Hasn’t done it since. Thanks for the feedback. Y’all stay safe!

 

Snow on the hood can easily get sucked into the cabin fresh air intake. This air/snow mix hits the hot heater core. The snow melts and evaporates. Gets into the cabin as humid air, then fogs the windows. Normal for winter driving.

Brush the snow off the hood and clear the cowl.
Run the defroster
Crack a window open about 1/2".